WEST ALLIS, WI-- Mitt Romney returned to Wisconsin today for the first time since August, delivering his closing argument speech in a state where Republicans hope they can manage a chink in the President Barack Obama's Midwestern armor.

Romney received a raucous welcome from an overflow crowd of 4,000 Wisconsinites chanting "four more days" this morning, welcoming the Republican presidential nominee with some of the loudest support Romney has won since returning to a full campaign schedule in the aftermath of Hurricane Sandy.

"What a great state. What a great welcome, and by the way this state is going to help me become the next president of the United States," Romney said, taking the stage following an introduction from the state's once-embattled Republican Gov. Scott Walker.

"I want to thank you for all that you've done and all you're going to do in the next four days and I want to tell you how much I appreciate being in the home of the next vice president of the United States," Romney said moments later, referring to his running mate Paul Ryan, who was born and raised in nearby Janesville, Wisc.

For the Romney campaign, the presence of a native son of the Badger state on the ticket, along with Walker's strong performance in this summer's failed recall effort, highlight an opportunity to solve a vexing problem -- how to break through Obama's Midwestern firewall.

"They woke a sleeping giant here I would say during the recall," Milwaukee business owner Frank Orlando told NBC News, adding that he was volunteering for a political campaign -- Romney's -- for the first time in his life. He added that half the volunteers he works with are also engaging in politics directly for the first time that cycle.

Recent polling lends some credence to that theory. An NBC News/Wall Street Journal/Marist poll released earlier this week showed Romney cutting Obama's lead in Wisconsin down to three points -- 49 to 46 percent -- half of what it had been a month prior and within the poll's margin of error.

With the president under the 50 percent threshold, Wisconsin's 10 electoral votes could help Romney succeed on Tuesday should he fail to break through in the race's most critical battlefield of Ohio, where he'll campaign the rest of the day Friday, and return later in the weekend.

For the Romney campaign, Wisconsin has already proven decisive once. The state's primary in April, which Romney won handily, was the last truly competitive contest between Romney and Rick Santorum, and helped wrap up the contentious GOP primary race later that month.